Question: Using a recorded adhan on the cellphone to notify a person for the time [of prayer], is this [something] agreeable or not?
Answer: “If the purpose is to notify him and it does not harm anyone, that is, if some people are reciting Quran in the Masjid and the cellphone calls with the adhan or other than it, then [this] disturbs the people. If it is with him in the house and it is adjusted to [notify him] for the prayer, and it does not harm anyone, then there is no harm” .
You can also refer to a similar fatwa on the blog here: http://darussaafi.com/?p=1593
Faisal Ibn Abdul Qaadir Ibn Hassan